Abstract: A leakage detection system includes: a gas supply line along which boil-off gas is supplied to a compressor; a reliquefaction line along which the compressed boil-off gas is cooled and reliquefied through a heat exchanger and is returned to a storage tank; a refrigerant circulation line along which a refrigerant is circulated; a refrigerant compressor to compress the refrigerant discharged from the heat exchanger; a refrigerant expander expanding and cooling the compressed refrigerant compressed by the refrigerant compressor and having been cooled through the heat exchanger and supplying the cooled refrigerant back to the heat exchanger; and a refrigerant charge line connecting an inventory tank filled with nitrogen to an upstream side of the refrigerant compressor. Upon initial start-up or restart of a reliquefaction process, the nitrogen is supplied to the upstream side of the refrigerant compressor via the refrigerant charge line to detect leaks in the refrigerant circulation line.

Abstract: Disclosed herein is a micro-leak detection system of a reliquefaction system for ships. The micro-leak detection system includes: a reliquefaction system reliquefying boil-off gas generated from a liquefied gas stored in a storage tank in a ship by recovering cold heat from the boil-off gas in a heat exchanger, compressing the boil-off gas, and cooling the compressed boil-gas in the heat exchanger through heat exchange with refrigerant circulated along a refrigerant circulation line; a heater heating the boil-off gas to be supplied from the storage tank to the heat exchanger through heat exchange with an antifreeze liquid; and a micro-leak detection device connected to a drain port through which a remaining liquid is drained from the heater and detecting small leaks in the heater.

Abstract: An electrolyte membrane includes a polymer electrolyte having a novel structure and a high-temperature polymer electrolyte membrane fuel cell including the same.

Abstract: A semiconductor device may include a first source line driving circuit that drives a first source line, a second source line driving circuit that drives a second source line, a first memory block including a plurality of first memory strings coupled between the first source line and a plurality of bit lines, respectively, and a second memory block including a plurality of second memory strings coupled between the second source line and the plurality of bit lines, respectively.

Abstract: A semiconductor device may include a first memory block including at least one first string that is connected between at least one first bit line and a first common source line, a second memory block including at least one second string that is connected between at least one second bit line and a second common source line, and a bit line connection circuit connected between the first bit line and the second bit line and configured to electrically connect or separate the first bit line and the second bit line.

Abstract: Disclosed is a high-temperature polymer electrolyte membrane fuel cell, in which electrodes of the fuel cell include a polymer containing a phosphoric acid group and a binaphthyl group, thereby preventing phosphoric acid poisoning of a catalyst due to strong interaction with phosphoric acid and porosity and increasing electrochemical performance.

Abstract: Disclosed is a BOG reliquefaction system. The BOG reliquefaction system includes: a compressor compressing BOG; a heat exchanger cooling the BOG compressed by the compressor through heat exchange using BOG not compressed by the compressor as a refrigerant; a pressure reducer disposed downstream of the heat exchanger and reducing a pressure of fluid cooled by the heat exchanger; and a second oil filter disposed downstream of the pressure reducer, wherein the compressor includes at least one oil-lubrication type cylinder and the second oil filter is a cryogenic oil filter.

Abstract: An ultrasonic NDT method and system, which can extract and analyze a defect signal even when a signal reflected from a defect interferes with a unique initial pulse of an ultrasonic transducer or a signal reflected from the surface of a test object, and an autoencoder-based prediction model training method used therefor. The method may include acquiring a measured signal by transmitting an ultrasonic wave to a test object and receiving an ultrasonic wave reflected from the test object; inputting the measured signal to an autoencoder-based prediction model and predicting a reference signal which is to be expected to be measured from a test object with no defect; calculating a residual signal as the absolute value of a difference between the measured signal and the reference signal; and analyzing information on a defect contained in the test object by analyzing the residual signal.

Abstract: According to an embodiment of the present disclosure, a memory device includes a memory cell array including a plurality of planes; a charge pump configured to generate an operating voltage used for an operation on each of the plurality of planes according to a first clock signal having a first cycle; page buffers each configured to store pass data representing whether an operation of each of the plurality of planes has been completed; and an operation control circuit configured to, based on a number of the pass data received from the page buffers, control the charge pump to generate the operating voltage according to a second clock signal having a second cycle that is longer than the first cycle.

Abstract: A semiconductor device may include: a capacitor including a first source electrode, a second source electrode connected in common to a plurality of second access lines, each of the second access lines spaced apart from one another and located on different layers, and a first channel structure located on the first source electrode and penetrating through the plurality of second access lines; and at least one cell string located between a source line and a first access line, the at least one cell string including a second channel structure penetrating through the plurality of second access lines, the plurality of second access lines electrically separated from each other.

Abstract: Disclosed are a ship boil-off gas reliquefaction system and method. The boil-off gas reliquefaction system includes: a storage tank disposed in a ship and storing a liquefied gas; a compressor compressing boil-off gas generated from the liquefied gas; a reliquefaction apparatus reliquefying the compressed gas compressed in the compressor by cooling the compressed gas through heat exchange with a refrigerant circulating in a refrigerant circulation part; and a reliquefaction capacity controller controlling reliquefaction capacity of the reliquefaction apparatus, wherein, when a pressure value sensed at a vapor header through which the boil-off gas is discharged from the storage tank is lower than a preset low pressure value, the reliquefaction capacity controller reduces the reliquefaction capacity of the reliquefaction apparatus to maintain a pressure in the storage tank.

Abstract: A blow-down method is applied to a reliquefaction system in which boil-off is compressed by a compressor, cooled and reliquefied through a heat exchanger, and returned to the tank after passing through a gas-liquid separator. The reliquefaction system includes a pressure compensation line extending from a downstream side of the compressor to an upside of the gas-liquid separator without passing through the heat exchanger; and a nitrogen blanket line along which nitrogen is supplied to the pressure compensation line. In the event of a trip of the reliquefaction system, nitrogen is supplied to the pressure compensation line along the nitrogen blanket line and is delivered to the downstream side of the compressor to pass through the heat exchanger along the reliquefaction line such that the heat exchanger and the reliquefaction line are blown down to remove compressed gas and reliquefied gas therefrom while being subjected to nitrogen (N2) purging.

Abstract: The semiconductor light emitting device comprises a semiconductor light emitting chip, and first electrodes electrically connected to the semiconductor light emitting chip, with the first electrodes each having a planar area larger than that of the semiconductor light emitting chip, wherein lower surfaces of the first electrodes are exposed externally, and an insulating material is filled in-between inner lateral surfaces of the first electrodes.

Abstract: A boil-off gas reliquefaction system includes: a compressor compressing boil-off gas generated from liquefied gas stored in a storage tank in a ship; a reliquefaction line connecting the compressor to the storage tank and allowing the boil-off gas to be reliquefied and returned to the storage tank therealong; a heat exchanger disposed on the reliquefaction line and cooling the boil-off gas compressed by the compressor; a separator disposed on the reliquefaction line, separating the boil-off gas cooled by the heat exchanger into a gaseous phase and a liquid phase, and supplying separated liquefied gas to the storage tank; a nitrogen blanket line along which nitrogen is supplied to an upstream side of the separator; and a bypass line branched from of the reliquefaction line downstream of the heat exchanger and connected to the storage tank without passing through the separator.

Abstract: A semiconductor device includes a memory cell connected to a word line and a bit line. The semiconductor device also includes a line driving circuit configured to apply a program voltage to the word line. The semiconductor device further includes a page buffer comprising a plurality of latches comprising at least one dynamic latch and at least one static latch and configured to control a voltage level of the bit line after the start of a program operation. The semiconductor device additionally includes a control circuit configured to control the page buffer to program, into the memory cell, data that have been stored in the static latch or store the data in the dynamic latch based on a temperature of the semiconductor device, when receiving a pause command during the program operation.

Abstract: A purging system and a purging method for a boil-off gas reliquefaction apparatus for ships are disclosed. The purging system includes: a storage tank disposed in a ship to store a low-temperature liquefied gas and provided with an insulating portion including a vacuum insulation layer; a compressor compressing boil-off gas generated from the storage tank; a heat exchanger in which the compressed gas compressed in the compressor is cooled; and a refrigerant circulation line in which a refrigerant to be subjected to heat exchange with the compressed gas in the heat exchanger circulates, wherein, upon N2 purging of the reliquefaction apparatus, the purging system supplies N2 after suctioning and venting a gas from the refrigerant circulation line using a vacuum pump provided to maintain an internal vacuum state of the vacuum insulation layer of the storage tank.

Abstract: Provided herein is a memory device for driving charge pumps respectively included in memory dies. The memory device includes a first memory die including a first charge pump and a first pump control circuit, and a second memory die including a second charge pump coupled to the first charge pump through a pump line and a second pump control circuit coupled to the first pump control circuit through a control line. The first pump control circuit is configured to control the first charge pump to perform a pump operation of generating a pump voltage in response to a command received by the first memory die, and output an operation alarm signal through the control line, and the second pump control circuit is configured to control the second charge pump to perform the pump operation in response to the operation alarm signal.

Abstract: Disclosed are a system and method for reliquefaction of boil-off gas of a ship and a system and method for treating off-gas of a reliquefaction apparatus. The boil-off gas reliquefaction system includes: a compressor compressing boil-off gas generated from liquefied gas stored in an on-board storage tank; a heat exchanger cooling the boil-off gas compressed in the compressor; a refrigerant circulation line in which a refrigerant supplied to the heat exchanger circulates; a temperature raising line extending from the storage tank to the compressor; and a heater provided to the temperature raising line, wherein the heater heats the boil-off gas to a suitable input temperature of the compressor.

Abstract: A page buffer may include a bit line connection circuit configured to connect or disconnect a bit line and a first node, a plurality of latch circuits that is connected to the first node in common. The page buffer may further include, and logical operation circuit configured to perform a logical operation by using one or more of a voltage level of the first node and a voltage level of a second node as an input and to set the voltage level of the first node responsive to results of the operational operation.

Abstract: A gradient-index phononic crystal flat lens which controls the behavior of an acoustic wave having a designated frequency. The gradient-index phononic crystal flat lens may include one or more super cells each having a plurality of layers stacked in a vertical direction according to a target gradient index profile, wherein each of the layers is composed of an aggregate in which unit cells having scatterers formed with the same size in the centers thereof are arranged in a horizontal direction. The one or more super cells may each include a divider provided between the neighboring layers, and configured to force the acoustic wave to propagate in the horizontal direction within the gradient-index phononic crystal flat lens.